7-Hydroxymitragynine an indole

Indole

Indole is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring. Indole is a popular component of fragrances and the precursor to many pharmaceuticals. Compounds that contain an...

, is an active alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

 in the plant Mitragyna speciosa, commonly known as Kratom

Kratom

Kratom , Mitragyna speciosa, is a medicinal leaf harvested from a large tree in the Rubiaceae family native to Southeast Asia in the Indochina and Malesia floristic regions. The plant has been traditionally used for its medicinal properties.It was first formally documented by the Dutch colonial...

. It has opioid agonistic activity. "The potency, calculated using pD (2) values, was 30- and 17-fold higher than that of mitragynine

Mitragynine

Mitragynine, an indole alkaloid, is the most abundant active alkaloid in the plant Mitragyna speciosa, commonly known as Kratom.-Pharmacology:...

 and morphine

Morphine

Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...

, respectively. Antagonism of naloxone

Naloxone

Naloxone is an opioid antagonist drug developed by Sankyo in the 1960s. Naloxone is a drug used to counter the effects of opiate overdose, for example heroin or morphine overdose. Naloxone is specifically used to counteract life-threatening depression of the central nervous system and respiratory...

 on concentration-response curves for 7-hydroxymitragynine confirmed its opioid effect. These results suggest that the opioid effect of M. speciosa is mostly based on the activity of 7-hydroxymitragynine."

7-Hydroxymitragynine is orally active in animals as an analgesic

Analgesic

An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

, and produces normal opioid side effects including constipation

Constipation

Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...

 development of tolerance

Tachyphylaxis

Tachyphylaxis is a medical term describing a decrease in the response to a drug due to previous exposure to that drug. Increasing the dose of the drug may be able to restore the original response. In this context tachyphylaxis is a synonym for drug tolerance...

 and withdrawal syndrome upon abstinence. The O-acetyl

Acetyl

In organic chemistry, acetyl is a functional group, the acyl with chemical formula COCH3. It is sometimes represented by the symbol Ac . The acetyl group contains a methyl group single-bonded to a carbonyl...

 ester

Ester

Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

, 7-acetoxymitragynine has also been reported and found to be an active μ-opioid agonist.